It is a soft-bodied mollusk that contains a flattened internal shell. This is a hermaphroditic species and can use both female and male sex organs. While mating individuals can be seen creating long chains. Each individual donates sperm to the one in front of it, while it receives sperm from the individual behind. They typically feed on algae and bacterial films and when in danger they squirt out purple ink for confusion and to defend themselves. The purple ink can actually harm fish if it is well concentrated. This little fellow was very close to the shore and not moving. I moved it out in deeper waters, but it may have been waiting for the tide to fully come in before swimming again. No ink was squirted. The pattern on its body reminds of crystal glazes on pottery.
Sorry. The video didn't come out very well, but it's interesting to watch the movement.
![](https://s2.save4k.ru/pic/huxj-CQ9yBQ/mqdefault.jpg)